1. Field of Invention
The present invention relates to a manufacturing process for enhancing light reflective rate in a reflective type display device.
2. Description of Related Art
Display devices are becoming slimmer, lighter and have a large screen. Especially, a large screen display device is an ongoing subject in current display technologies. Projection TVs are typical examples of the large screen display device.
Projection TVs are largely classified into CRT (Cathode Ray Tube) projection TVs and LCD (Liquid Crystal Display) projection TVs. The LCD projection TVs are classified into transmissive LCD-based systems or reflective LCD-based systems.
In the reflective LCD-based systems, a particular type of reflective LCD panel known as a liquid crystal on silicon (LCOS) display panel is used. The LCOS display panel uses reflective LCD elements arranged on a silicon backplane. LCOS display panels can be used in both single-panel and three-panel configurations, and are becomingly increasingly popular for use in applications such as compact projectors and head-up or near-to-eye projection display systems. LCOS display panels have a number of significant advantages over other types of reflective LCD panels. For example, crystalline silicon can be used to form active matrix elements of the LCOS panels. The silicon backplane can also be used to form the TFT drivers, timing controller and other functional circuitry, using well-known and efficient semiconductor manufacturing techniques. Moreover, a larger percentage of the active area can be used for processing video information for display.
In a reflective LCOS system, light reflection rate is a key factor to improve brightness of the system. During the prior manufacturing process of the LCOS display panel, a top metal layer is flat. However, the flat top metal layer may have some disadvantages concerning light reflection rate. Now please refer to FIG. 1 which shows light reflection in a reflective LCOS system. To be within the detection range for being detected by front side detection configuration (not shown), an incident light beam 101 should have an incident angle perceivable by the detection range, so after reflection, the reflected light beam 101 will be detected without light loss. If an incident light beam 103 has an incident angle non-perceivable by the detection range, after reflection, the reflected light beam 103 will not be detected, i.e. there is light loss.
There is a need to enhance the light reflection rate to approach high brightness requirement in the reflective LCOS system.